JP7389591B2 - How to process flat wire - Google Patents

Description

The present invention relates to a method for processing a rectangular wire.

In stator coils that constitute rotating electric machines (motors) installed in automobiles, rectangular wires are used as conducting wires to improve the space factor. This kind of flat wire is processed by cutting the flat wire to a predetermined length, peeling off the coating on the tip of the flat wire, and exposing it as a pre-processing process before joining the flat wires to form a coil. A process of chamfering each corner of the conductive wire portion is performed (for example, Patent Document 1).

JP2014-60860A

As one of the above chamfering steps, chamfering is performed on the edge side of the cut surface formed on the rectangular wire, which is provided on one side or the other side of the cutting direction and extends in a direction perpendicular to the cutting direction. In the process, only one edge side in the cutting direction is chamfered, and the other edge side is left unchamfered as a surface to be welded to another flat wire during coil forming.

However, during the subsequent welding process, sag caused during the cutting process may sometimes become a problem. In other words, sagging occurs on one edge of the cut surface in the cutting direction, but if the side where this sag occurs becomes the welding surface during coil forming, the welding surfaces will not be properly welded together, resulting in poor welding. There was the issue of putting it away. Alternatively, it is possible to always chamfer the sag side and manage the welding surface on the opposite side, that is, on the downstream side in the cutting direction, but this would increase management costs and other problems. It wasn't on point.

By the way, in the conventional cutting process, as shown in FIG. 7, with a pair of die blades 42 in contact with the lower surface side of the flat wire 1, a punch blade 41 having a certain width is inserted from the upper surface side of the flat wire 1. By pressing down, the material was cut off by the width of the punch blade 41, and the flat wire 1 was cut. However, in this case, material was wasted by the amount of the cut-off portion X having the same width as the punch blade 41, which caused a reduction in yield.

Therefore, in order to improve the yield, the clearance between the punch blade and the die blade is set to zero or extremely small (see punch blade 32 and die blade 33 in Fig. 3(a)), and the rectangular wire 1 is sheared by pushing the punch blade, and the excess It is possible to prevent the occurrence of cut-off portions. However, in this case, there was a problem in that the sag that occurs on the cut surface tends to become large, and the problem of the above-mentioned welding failure becomes noticeable.

In order to solve the above problems, the present invention presses a first blade against a flat wire from one side thereof, and presses a second blade against the other side of the flat wire opposite to the one side. cutting the rectangular wire in a direction perpendicular to its length by pressing the rectangular wire downward toward the one side , and cutting the rectangular wire into a predetermined length; A method for processing a rectangular wire, comprising a chamfering step of chamfering only one end edge of the other end edge by applying pressure with a pressure member, wherein the chamfering step chamfers only one edge of the one side edge of the other side edge, the chamfering step While the other end edge side of the flat wire is supported by the surface from the side opposite to the pressing direction of the pressure member , the one end edge side is supported by the pressure member from the other side. It is characterized in that this is carried out by applying pressure in the direction of the edge to plastically deform the rectangular wire.

According to the present invention, even if there is a sag during cutting on the side opposite to the chamfering side of the rectangular wire, the sag can be removed by plastically deforming the rectangular wire by applying pressure in the subsequent chamfering step. Therefore, it is possible to prevent welding defects when welding flat wires together.

In particular, if the processing method of the present invention is used, even when the above-mentioned cutting method that tends to cause large sag is employed, the above-mentioned welding defects can be prevented, and the yield of the material can be improved.

According to the present invention, sagging caused in the cutting process can be removed in the chamfering process, and subsequent welding defects can be prevented.

FIG. 3 is a perspective cross-sectional view of a flat wire. (a) is a diagram showing the state of horizontal peeling, and (b) is a perspective view of the rectangular wire after horizontal peeling. (a) is a diagram showing the cutting process, and (b) is a perspective view of the rectangular wire after cutting. It is a figure which shows the state before chamfering processing. (a) is a diagram showing the state during chamfering, and (b) is a perspective view of the rectangular wire after chamfering. FIG. 2 is a flowchart showing a process of processing a rectangular wire according to the present embodiment. It is a figure which shows an example of the cutting method of a flat wire.

Embodiments of the present invention will be described below based on the drawings.

As shown in FIG. 1, the rectangular wire 1 has a copper wire 11 serving as a conducting wire and a coating 12 covering the periphery of the copper wire 11, and has a rectangular cross section. Note that in FIG. 1 and subsequent figures, the cross section is shown as a perfect rectangle for convenience, but in reality, the corners thereof are curved.

The method for processing a rectangular wire according to the present embodiment will be described below with reference to flowcharts shown in FIGS. 2 to 5 and 6.

The rectangular wire 1 has circumferential cuts L1 and L2 made at two locations in the length direction by a pre-cutting process (step S1 in FIG. 6).

Then, in the horizontal peeling step, the coatings on two opposing sides of the flat wire 1 are peeled off (step S2). Specifically, as shown in FIG. 2(a), a pair of peeling holes are formed on the upper and lower surfaces of the rectangular wire 1 at positions facing the longitudinal notches (see L1 and L2 in FIG. 1). Apply the blade 31 and slide it in a direction perpendicular to the plane of the paper in FIG. 2(a) to remove the film 12 on the upper and lower surfaces. As a result, as shown in FIG. 2(b), the copper wire 11 is exposed on a part of the upper and lower surfaces of the rectangular wire 1 (the section corresponding to the cut L1 to the cut L2 in FIG. 1). A section 13 is formed.

Next, in the cutting process, the rectangular wire 1 is cut into a predetermined length (step S3). Specifically, as shown in FIG. 3(a), by pressing the die blade 33 from the bottom side of the flat wire 1 and pushing down the punch blade 32 from the top side, the flat wire 1 is perpendicular to the length direction. Shear in the direction and cut to the specified length. Note that a support member may be provided on the lower surface side of the flat wire 1 on the cutting side to prevent the flat wire 1 from falling during shearing.

The cutting position in the length direction of the flat wire 1 is the position of the exposed portion 13, and as shown in FIG. 3(b), the exposed portion 13 is arranged at the tip of the flat wire 1 after cutting.

Further, as shown in FIG. 3(a), the clearance in the length direction between the punch blade 32 and the die blade 33 is set to approximately 0. This makes it possible to avoid wasteful cutting off of the flat wire 1, but on the other hand, large sagging occurs at the top of the cut surface 14 of the flat wire 1 after processing (the sagging of the flat wire 1 in FIG. 4). See part A. However, FIG. 4 is upside down from FIG. 3(a). In addition, the sag part A is omitted in FIG. 3(b).

Next, in a chamfering step, one corner (upper side in FIG. 3(b)) of the corners formed by the cut surface 14 of the flat wire 1 and the exposed portion 13 is chamfered (step S4). In other words, in the present embodiment, only one of the corner portions on the edge side of the wide side is chamfered, among the corner portions on the edge side of one side and the other side in the cutting direction of the cut surface 14.

Specifically, as shown in FIG. 4, the rectangular wire 1 is placed on the receiving member 35 with one exposed portion 13 facing upward. Note that the illustrated example shows a case where the sagging portion A is arranged on the receiving member 35 side.

Then, a coining punch 34 as a pressing member is pressed against the corner of the rectangular wire 1 from above. The coining punch 34 is provided with a pressing surface 34a, which is an inclined surface, on the side facing the flat wire 1.

As shown in FIG. 5(a), the rectangular wire 1 is pressed downward by the coining punch 34 (in other words, toward the other edge of the cut surface 14 in the cutting direction), so that the upper surface of the tip thereof The side is plastically deformed into a shape that follows the pressure surface 34a, and is chamfered. Also, due to this pressurization, the lower surface side of the rectangular wire 1 is pressed against the receiving member 35 and flattened, and the sagging portion A formed in the cutting process is removed. Through the above steps, a chamfered portion 15 is formed on the upper surface side of the tip end of the rectangular wire 1, as shown in FIG. 5(b).

In this manner, in this embodiment, even if the sagging portion A is placed on the opposite side to the side to be chamfered, the lower surface side can be flattened and the sagging portion A can be removed by applying pressure by the coining punch 34. . In this embodiment, the case is shown in which the pressing direction by the coining punch 34 is downward in the figure, which is the same direction as the cutting direction of the flat wire 1, but when pressing is applied at an angle to the downward direction, However, it goes without saying that the sagging portion A can be removed by the downward component of the pressing force.

By the way, the surface (lower surface in FIG. 5(a)) opposite to this chamfered side and substantially perpendicular to the cut surface 14 is a welding surface to be welded during coil forming. That is, by the chamfering process of this embodiment, it is possible to prevent the sagging portion A from remaining on the welding surface during stator coil molding, and it is possible to prevent welding defects between the rectangular wires. Therefore, even when a cutting method that causes large sagging as shown in FIG. 3(a) is adopted, the above-mentioned welding defects can be prevented. In other words, the processing method of this embodiment can prevent welding defects, improve the yield of the material for the flat wire 1, and reduce the manufacturing costs of the flat wire 1 and the stator coil.

Furthermore, by performing chamfering by plastic deformation due to pressure, chamfering can be performed without producing chips, unlike in the case of cutting. Therefore, it is also preferable in terms of quality control during the manufacturing process.

The flat wire 1 that has undergone the chamfering process is then chamfered at the corners formed by the edges of the narrow side of the cut surface 14 (the left and right sides in FIG. 5(b)) and in the length direction of each exposed portion 13 side. After passing through a chamfering process in which corners formed by each extending edge are chamfered and a vertical peeling process in which the coating is peeled off on a surface perpendicular to the horizontal peeling process, it is assembled as a stator coil. Note that these steps are omitted in the flow diagram of FIG. By chamfering each part of the flat wire 1, insertability of the flat wire 1 into the slot of the stator core can be ensured during coil forming.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

1 Flat wire 11 Copper wire (conductor wire)
12 Film 13 Exposed part 14 Sheared surface 15 Chamfered part 31 Peeling blade 32 Punch blade 33 Die blade 34 Coining punch (pressure member)
34a Pressure surface 35 Receiving member A Sagging portion L1, L2 Notch

Claims (1)

By pressing a first blade against the flat wire from one side thereof, and pressing a second blade against the other side of the flat wire opposite to the one side and pushing it down toward the one side, the flat wire is a cutting step of cutting the material into a predetermined length in a direction perpendicular to its length;
Processing of a flat wire, comprising a chamfering step of chamfering only one edge of the one side edge and the other side edge of the cut surface of the flat wire by applying pressure with a pressure member. A method,
In the chamfering step, the other end edge of the rectangular wire is supported by the flat surface of the receiving member from the side opposite to the pressing direction of the pressing member , and the pressing member chamfers the one side. A method for processing a rectangular wire, characterized in that the processing is carried out by pressurizing the edge side toward the other edge to plastically deform the rectangular wire.

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